Problem: Simplify the following expression: $a = \dfrac{4}{5q} + \dfrac{1}{8q}$
In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $5q$ and $8q$ $\lcm(5q, 8q) = 40q$ $ a = \dfrac{8}{8} \cdot \dfrac{4}{5q} + \dfrac{5}{5} \cdot \dfrac{1}{8q} $ $a = \dfrac{32}{40q} + \dfrac{5}{40q}$ $a = \dfrac{32 +5}{40q}$ $a = \dfrac{37}{40q}$